Therefore, blockchain provides a framework in which nodes can maintain an immutable ledger of data. In Fig. REF , we illustrate how immutability is created in blockchain by linking successive blocks together using cryptographic hashing functions. Currently PoW is the most widely used mechanism for mining. However, PoW requires a substantial computing power and therefore uses considerable amounts of energy, a notable drawbacks of PoW. To solve this issue, another mining mechanism, Proof-of-Stake (PoS) is becoming popular. PoS provides faster transactions and uses less energy during mining [1]}. Some significant properties of blockchain are outlined as follows [2]}:
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